The Wolves have been defeated, but our tet faces yet another catastrophe. Susannah Dean’s body has been usurped by a demon named Mia who wants to use Susannah’s mortal form to bear a demon child. Stealing Black Thirteen, Mia has traveled through the Unfound Door to 1999 New York where she plans to give birth to her chap, a child born of two mothers and two fathers who will grow up to be Roland’s nemesis. With the help of the time-traveling Manni, Roland and Eddie plan to follow Susannah while Father Callahan and Jake will find Calvin Tower, owner of the vacant lot where a magical rose grows: a rose that must be saved at all costs. But despite our ka-tet’s intentions, ka has its own plans. Jake, Callahan, and Jake’s bumbler companion are transported to New York to follow Susannah, while Eddie and Roland are tumbled into East Stoneham, Maine, where they are greeted by Eddie’s old enemy, the gangster Balazar. But it isn’t just bullets that Roland and Eddie must brave. Soon they will meet their maker, in the form of a young author named Stephen King.

Roland and his tet have just returned to the path of the Beam when they discover that they are being followed by a group of inexperienced trackers. The trackers are from the town of Calla Bryn Sturgis, and they desperately need the help of gunslingers. Once every generation, a band of masked riders known as the Wolves gallop out of the dark land of Thunderclap to steal one half of all the twins born in the Callas. When the children are returned, they are roont, or mentally and physically ruined. In less than a month, the Wolves will raid again. In exchange for Roland’s aid, Father Callahan—a priest originally from our world—offers to give Roland a powerful but evil seeing sphere, a sinister globe called Black Thirteen which he has hidden below the floorboards of his church. Not only must Roland and his tet discover a way to defeat the invincible Wolves, but they must also return to New York so that they can save our world’s incarnation of the Dark Tower from the machinations of the evil Sombra Corporation.